Smoke generator

ABSTRACT

A smoke generator for providing smoke to a food smoking cabinet includes an upright enclosure with a fuel storage area located above a combustion chamber. An operating rod assembly including an operating rod, partition, and fuel agitator extend downwardly into the pellet fuel storage area. The operating rod may be manipulated from outside the enclosure to operate the agitator and selectively reposition the partition and agitator within the fuel storage area of the enclosure.

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

BACKGROUND

This invention relates to pellet fueled smoke generators that may beused to supply smoke to a smoker cabinet or a BBQ unit to flavor orpreserve food. Although many food smokers have a smoke source within thecabinet, such as disclosed in U.S. Pat. No. 4,810,510 and patentapplication Ser. No. 12/432,568, other smokers use external wood pelletfueled smoke generators to supply smoke to a food-containing smokercabinet. Examples of such external smoke generators are described inU.S. Pat. Nos. 7,681,493; 6,705,213; 4,232,597; and 3,788,3201; and U.S.patent application Ser. No. 11/303,405. Smoke from wood fuel pelletsincludes carbon dioxide, water vapor and creosote. It is the creosotewhich imparts the smoky flavor to the food and helps to preserve thefood. Some of the smoke generators listed above employ hoppers to storethe fuel pellets above the combustion area such that the pellets willfall from the hopper into the combustion area. Several disadvantages areassociated with this arrangement. As smoke rises from the fuelcombustion area into the pellet storage hopper, creosote is deposited onthe cool walls of the hopper. On occasion the pellets will form abridging matrix that prevents pellets from falling into the combustionarea.

The present invention discloses an improved apparatus for generatingsmoke for food preservation and flavor from wood based fuel pellets. Theapparatus includes an enclosure having a fuel storage area and acombustion chamber. An operating rod extends into the fuel storage areaand is attached to a movable partition dividing the fuel storage areaand/or movable fuel agitator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary smoke generator of thepresent invention.

FIG. 2 is a perspective view of the cap and operating rod assembly ofthe exemplary embodiment.

FIG. 3 is a partial sectional view of the smoke generator of FIG. 1along lines 3-3 of FIG. 1.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

Referring to FIGS. 1 and 3, an exemplary embodiment of the smokegenerator 10 includes a housing 12, a combustion and fuel storageenclosure 14, a blower 16, a heating element 18, and a thermostat 20.The housing 12 includes vents 13 to permit air to enter the housing. Asmoke pipe 23 extends through a sidewall of the housing 12.

The combustion and fuel storage enclosure 14 includes a screen 24 forsupporting fuel pellets 26 above an air chamber 28. An opening in thelower part of the enclosure 14 accommodates a passageway 30 from theblower 16 to the air chamber 28 a heating element 18 and a smoke outlet22. A smoke pipe 23 carries smoke from the smoke outlet to a smokercabinet or the like. The portion of the enclosure 14 above the screen 24and in the vicinity of the heating element 18 and smoke outlet 22 is thecombustion chamber 32. The fuel storage area 34 is generally the entireenclosure 14 above the smoke outlet 22. A sleeve 36 supports theenclosure 14 within the housing 12 and acts as a heat sink to dissipatethe heat generated in the combustion chamber 32. Preferably theenclosure and sleeve are of non-combustible material such as metal. Thethermostat 20 is attached to and in thermal connection with the sleeve36. The uppermost portion of the enclosure 14 includes exterior lugs 38for use in securely closing the top 40 of the enclosure as will bedescribed below. The top 40 of the enclosure 14 defines an opening 42through which fuel pellets 26 may be deposited into the enclosure. Acollar 70 of heat resistant material prevents material such as ash dustand pellets from entering housing 12.

Turning to FIG. 2, a cap 43 and an operating rod assembly 44 is shown.The cap 43 serves as a cover to close the opening 42 at the top 40 ofthe enclosure 14. The cap 43 includes L-shaped slots 48 to receive andengage the lugs 38 to securely close the top 40 enclosure 14. Aresilient gasket 54 preferably of a rubber-like material fits againstthe underside of the cap. The cap 43 includes a central aperture 50through which extends an elongate operating rod 52. The gasket 54 alsoincludes a corresponding central aperture through which passes theoperating rod 52. The operating rod assembly 44 includes a partition 56and fuel agitator 58 which are attached to the lower end of theoperating rod 52. In the exemplary embodiment, the partition 56 closelymatches the interior of the enclosure 14. A knob 60 on the upper end ofrod 52 facilitates manipulation of the rod to provide axial androtational movement of the rod 52.

In the exemplary embodiment, the metal enclosure 14 conducts heat to thesleeve 36 to which the thermostat 20 is thermally coupled. If thetemperature of the sleeve 36 proximate to the thermostat 20 falls below185° F., the heating element 18, such as a glow plug, is activated. Inthe preferred embodiment, the blower 16 continuously forces air throughthe passageway 30 into the air chamber 28 at the bottom of the enclosureand upwardly into the combustion chamber 32.

Fuel in the form of compressed wood fiber pellets 26 in the exemplaryembodiment is loaded into the enclosure 14 through opening 42 at the topof the enclosure. The fuel pellets fall into the combustion chamber 32,where they are supported on the screen 24 in the vicinity of the heatingelement 18. Preferably only an appropriate amount of fuel pellets isloaded into the enclosure 14 to accomplish the smoking at hand. While itis possible to fill the enclosure 14 to the top, it is not necessary todo so for each use.

Engaging the lugs 38 with the L-shaped slots 48 in the cap 46 andtwisting the cap creates a substantially air-tight seal because theresilient gasket 54 is compressed between the edge 62 of the opening 42and the underside of the cap 46. The gasket 54 tightly surrounds theoperating rod 52 where the rod passes through the gasket to prevent freepassage of air into and out of the enclosure 14. In the exemplaryembodiment, the operating rod 52 is straight, defining an axis, andpushing or pulling on the knob 60 moves the rod and the attachedpartition 56 and agitator 58 along the rod's axis. Pushing down on theknob 60 moves the operating rod 52, partition 56 and agitator 58 into aposition where the agitator 58 extends down into the fuel pellets 26 andthe partition 56 is directly above the fuel pellets 26, partitioning thefuel storage area 28 into a fuel-containing portion 64 and a fuel-freeportion 66. The size of these portions 64 and 66 will vary dependingupon the amount of fuel in the enclosure 14 and the position of thepartition 56.

When the smoke generator is loaded with wood pellets as described aboveand connected to a power source, the glow plug 18 heats up and air fromthe blower 16 flows upwardly from the air chamber 28 through the screen24 into the combustion chamber 32. The wood pellets in the vicinity ofthe heating element ignite and generate smoke which exits the combustionchamber through the smoke outlet 22 and smoke pipe 23. The relativelysmall size of the smoke outlet 22 restricts the air flow through thecombustion chamber, providing sufficient air flow to enable smolderingcombustion of the fuel pellets, but discouraging vigorous combustion.Although smoke also fills the fuel containing portion 64 of theenclosure 14, the placement of the partition 56 confines the size ofthis area to that necessary accommodate the volume of the fuel pellets26. The smoke is confined to the heated fuel-containing portion 64 ofthe storage area and does not contact the cooler walls of the fuel-freeportion 66, discouraging formation of creosote deposits on the enclosurewalls.

The partition 56 conforms closely to the inner dimensions of theenclosure 14 shielding the resilient gasket 54—which is preferably madeof heat resistant material—from unnecessary heat which would degrade thematerial of the gasket and impair the seal.

If the pellets 26 form a bridging matrix and do not freely fall into thecombustion chamber 32, rotation of the operating rod 52 by manipulatingthe knob 60 will move the agitator arms 68 which extend radiallyoutwardly from the axis of the operating rod 52. Movement of theagitator arms 68 stirs the fuel pellets 26, breaking up any bridgingmatrix and causing the pellets to fall into the combustion chamber 32.While the agitator 58 is shown in the exemplary embodiment as a simplewing nut, an agitator may be of any shape and size sufficient to movethe fuel pellets when the operating rod 52 is manipulated.

If the fuel pellets 26 have burned sufficiently such that the level ofpellets within the enclosure 14 has fallen out of contact with theagitator 58, the operating rod 52 may be moved downwards until theagitator is again in contact with the pellets.

When operational, the smoke generator 10 is preferably positioned nextto a smoker cabinet or the like with the smoke pipe 23 extending intothe cabinet (not shown). The smoke pipe 23 may be threaded, in whichcase a nut may be used to engage the threads and secure the smokegenerator 10 to the cabinet. A bracket, not shown, may also be used tosupport and secure the smoker generator to a cabinet or the like.

The terms and expressions which have been employed in the foregoingspecification are used therein as terms of description and not oflimitation, and there is no intention in the use of such terms andexpressions of excluding equivalents of the features shown and describedor portions thereof, it being recognized that the scope of the inventionis defined and limited only by the claims which follow. For example, theenclosure does not need to be in the shape of a vertically orientatedcylinder nor does the fuel storage area have to be directly above or thesame shape as the combustion chamber. Any arrangement which enables thefuel pellets to be drawn by gravity into the combustion chamber iswithin the scope of the invention. The operating rod may be of any shapeor configuration as long as it is capable of either moving the shield ormoving the agitator from outside the enclosure.

What is claimed is:
 1. A smoke generator, comprising: (a) a lowercombustion chamber and an upper fuel storage area configured so as toenable fuel in said storage area to be drawn by gravity into saidcombustion chamber; (b) a partition positioned in said fuel storage areadividing said fuel storage area into a fuel containing portion and asubstantially fuel-free portion, wherein said partition is selectivelymovable within said storage area to increase or decrease the fuel-freeportion of the fuel storage area.
 2. The smoke generator of claim 1including a fuel agitator positioned in said fuel storage area andcapable of agitating fuel in the vicinity of said agitator.
 3. The smokegenerator of claim 2 including an operating member operatively connectedto said agitator and operable from outside said fuel storage area toselectively agitate fuel within said fuel storage area.
 4. The smokegenerator of claim 2 wherein said operating member is capable of bothoperating said agitator and repositioning said agitator within said fuelstorage area.
 5. The smoke generator of claim 1 including an operatingmember attached to said partition and operable from outside said fuelstorage area to selectively reposition said partition within saidstorage area.
 6. The smoke generator of claim 5 further including a fuelagitator operatively associated with said partition, such thatrepositioning said partition within said storage area also repositionssaid agitator.
 7. The generator of claim 5 wherein said fuel storagearea includes a cover, said operating member passing through a hole insaid cover, substantially blocking air flow into and out of said fuelstorage area through said hole.
 8. The smoker generator of claim 1including an operating member extending into said fuel storage area andoperable from without said fuel storage area to selectively repositionsaid partition within said fuel storage area.
 9. The smoke generator ofclaim 8 wherein said operating member is elongate defining an axis, andis operatively connected to said partition to move said partition infirst and second directions along said axis.
 10. The smoke generator ofclaim 9 including a fuel agitator operatively connected to saidoperating member such that movement of said operating member along saidaxis repositions said agitator within said fuel storage area.
 11. Thesmoke generator of claim 10 wherein movement of said operating memberabout said axis rotates said agitator.
 12. The smoke generator of claim10 wherein said operating member includes at least one arm extendingradially outwardly from said axis.
 13. The smoke generator of claim 1wherein said fuel storage area includes an opening to enable fuel to beplaced in said fuel storage area, a cover to close said opening and aresilient seal positioned between said cover and said opening tosubstantially prevent air flow through said opening.
 14. A smokegenerator comprising: (a) a combustion chamber and a fuel storage area,at least a portion of said fuel storage area containing fuel material;(b) a fuel agitator, operable from outside said fuel storage area toselectively reposition said agitator within said fuel storage area andagitate said fuel material;
 15. The smoke generator of claim 14 furtherincluding a partition, selectively movable from outside said enclosureto reposition said partition within said fuel storage area.
 16. Thesmoke generator of claim 14 further including an operating member,operatively associated with said agitator and selectively operable fromoutside said fuel storage area to reposition said agitator and agitatesaid fuel material.
 17. The smoke generator of claim 14 wherein saidfuel agitator may be selectively operated from outside said fuel storagearea to agitate said fuel without repositioning said agitator withinsaid enclosure.
 18. The smoke generator of claim 16 wherein saidoperating member is operatively associated with a partition movablewithin said fuel storage area to divide said fuel storage area between afuel containing portion and a portion which is substantially fuel-free.19. In a smoke generator having an enclosure defining a fuel storagearea, an operating rod assembly including a fuel agitator operativelyassociated with an operating rod, said operating rod selectively movableto reposition said fuel agitator within said fuel storage area.
 20. Thesmoke generator of claim 19 further including a partition operativelyassociated with said operating rod and selectively movable within saidfuel storage area to divide said fuel storage area into compartments.